Sunday, December 11, 2011

Friday was my last day at Bump Technologies. It's been a little shorter ride there than I expected, but still a very rewarding one. Before Bump I had been at eBay for four years, so you might think that going to a startup was a big change for me. Actually Bump was the sixth startup that I have worked at. Of the non-startups that I worked at was a very small consulting company that was much more like a startup than not. Still I'll leave the number at six. How have those startups fared?

Two burned out pretty quickly. One of those never got more than angel money, while the other got an $8M series A that it burned through more rapidly than I can understand.

One was bought by Oracle and is now part of their business intelligence suite.

One turned profitable, but was shut down by its board because they no longer thought "hockey stick" growth was possible.

One labored for many years on minimal funding before selling its intellectual property and going out of business.

The other of course is Bump.

[Note: While all of the following is based on my experiences in aggregate, I had no one specific in mind while writing this little rant. In particular my comments on 'modern' startups does not reflect Bump.]

My first two startups were in 2000, almost twelve years ago and during the dot-com bubble. A lot has changed in that time. The capital needed for hardware has shrunk amazingly. Commodity hardware plus the rise of virtualized hosting a la Amazon web services, has led to a world where a startup's big spend is on engineering talent. The value placed on engineering is huge. Engineering is a scarce resource, as the supply of engineers is shrinking while the demand is rising. Further the notion of "10X engineers" is widely accepted, and this essentially lifts any kind of ceiling on the value of an engineer. Now as an engineer this is mostly a Very Good Thing, at least from my perspective. However there are some weird things that this leads to.

The high value of engineering can make for a strange situation in companies with non-technical founders. Just imagine a situation where you have to work hard to get something and continuously spend a lot just to keep that something, and you don't really understand what that something does. That can be hard to swallow and keep down. Now multiply that times five or ten or twenty "somethings." Yeah.

Of course startups have always loved young engineering talent fresh out of school. There has always been huge appeal in such engineers because they are very cheap and have much less of a life outside of work, so they are more likely to happily work the long hours necessary in a startup. With the value of engineering going up so much, the appeal of young engineers is much greater than it was twelve years ago. Go back and read the previous paragraph and consider that such an awkward situation can be avoided with younger engineers. The net result is you have "younger" startups in general where more is asked of young, inexperienced engineers. This can lead to some amazing opportunities for talented young engineers. It can also lead to Engineering Disasters like we've never seen before.

Another interesting change in the world of startups is the value of design. I attribute most of this to the amazing success of Apple and the high value they place on design. Now in Apple's case, I would say they place a higher value on user experience and design follows from that, but more on that subtle difference momentarily. The value of design has obviously lead to a greater role for designers. They are more empowered than ever before to insist on certain aspects of a product. However the value of design has also lead to a lot of "armchair designers". Everyone thinks design is important, and design is the kind of thing that everyone can form an opinion on. Of course we all think that our opinion is very valuable, so we feel strongly about our opinions on design.

Think about how often you hear somebody -- doesn't matter what their job is -- talk about how some website or app or whatever is awful or looks terrible or "broken." The bigger more popular the product is, the more likely it will illicit such responses. I hear developers constantly talking about how something is ugly or beautiful. Even better, I hear developers constantly talk about how most other developers don't care about design and that they are special because they do. It's hilarious.

It's at least as bad if not worse among so called product people in startups. When I was working for my first couple of startups, our product managers were people with some kind of unique experience and thus theoretically some unique perspectives into what our customers would want. Not so much today. The qualifications for being a product person in a startup is pretty minimal as best as I can tell. That doesn't stop the from waxing poetic about the aesthetics of websites and apps.

These product managers and developers may all think that they have a lot in common with Steve Jobs, but as I mentioned earlier, I think Apple's approach is a little different than the approach taken by most startups. I think Apple stresses user experience first and realize that this is not the same thing as product or design. In a startup people have to wear many hats, so a lot of these competing principles get rolled together into one product person who may have some dubious credentials.

The worst sin of startup product people is not their strong opinions on what looks good or bad. It's a tendency to base product decisions on their personal preferences. They think that a product should be exactly what they would find most useful or most cool. Now this is not some new and unique thing. Product managers at startups ten years ago were guilty of this too, as are product manager at big companies today. It's just the circumstances of product managers at modern startups make this situation worse, as does the form-over-function corollary that comes from the emphasis on visual design. It's a perfect storm that leads to products being designed around users with a thousand Facebook friends and 5 tumblr blogs who spend more time at speakeasies than at Target. Of course that might really be your user, but it is statistically unlikely.

I've probably said too much about the current state of startups. This is my blog though, so what about me? I seriously doubt that I'll stop at six startups, though of course I hope my current job lasts for a long time. Like so many other people working in Silicon Valley, I want to work on a product that can change the world. That's what has lead me to startups six times in my career. But startups aren't the only kind of companies that can change the world.

Thursday, December 08, 2011

This is the second post about mobile architecture. In the first post, I talked about how the evolution from web applications has led to architecture's centered around asynchronous access to remote resources using HTTP. I also mentioned how Android applications are able to benefit from cloud-to-device messaging (C2DM) to push new data to apps. The most common use for this is for push notifications, but C2DM is not limited to push notifications. The key to pushing data via C2DM is that it uses a persistent socket connection to the C2DM servers. So whenever any new data is sent to those servers, they can send it over this connection to mobile apps. Now you might think that there is something magical or even worse, proprietary, about using sockets within a mobile application. This is not the case at all. Any application can make use of sockets, not just ones written by Google. Actually that's not true. Any native applications on iOS and Android can use sockets. Socket support was recently added to Windows Phone 7 as well. For web apps there is the Web Socket API, but it is not yet implemented across platforms.

So what are the benefits of using sockets? Well there is the data-push capability that you see in C2DM. In general you can make a much faster app by using sockets. There is a lot of wasted time and overhead in making HTTP connections to a server. This wasted time and overhead gets multiplied by the number of HTTP calls used in your application. There is also overhead in creating a socket connection to a server, but you only pay it one time. The extra speed and server push-iness allows for very interactive apps. Sounds great, but how does this affect the application architecture? Here's an updated diagram.

The big difference here is that instead of requests and corresponding responses, we have events being sent from client to server and back again. Now obviously some of these events may be logically correlated, but our communication mechanism no longer encodes this correlation. The "response" to an event from the app does not come immediately and may not be the next event from the server. Everything is asynchronous. Now in our traditional architecture we also had "asynchronous things" but it was different. Each request/response cycle could be shoved off on their own thread or in their own AsyncTask for example. This is a lot different.

Let's take a simple example. One of the first things that many applications require a user to do is to login, i.e. send a combination of name and password and get some kind of authenticated materials in response (token). In a traditional architecture you would send a login request to the server, wait for the response, and then either get the token or display an error if there was a problem with the username+password combination. In an event driven architecture, your application fires a login event that contains the username+password. There is no response per se. Instead at some point in the future the server will fire an event indicating a successful login that includes a token, or an error that may contain a reason as well. You don't know when this will happen, and you may receive other events from the server before getting a "login response" event.

Logging in is just one example. There are numerous other things that are easy to think of in terms of request/response. The whole idea of REST architectures are built around this request/response cycle and HTTP. Doing a search, getting user information, posting a comment, the list goes on and on. Now of course it is possible to recreate the illusion of a request/response cycle -- just fire your request event and block until you get the response event. But clearly that is Doing It Wrong.

So maybe these event driven architectures are not right for all applications. Yes they are sexier, but don't try to put a square peg in a round hole. This kind of architecture is best suited for apps where you are interacting with somebody else. Let's say you are bidding on an auction. Somebody else bids on the same auction and ideally you will see this happen very quickly. Or maybe you sent a message to a friend on some type of social network, and you can't wait to see their response. Social games are also a great example of the types of apps that would benefit from an event driven architecture. Even if the game doesn't have to be real-time, it would probably still benefit from "lower latency" between moves.
Hopefully you have a better idea now on if your application should use a traditional architecture or an event driven one. Of course there is a lot of room in between. You could easily have an architecture that uses both, picking the right interaction model depending on the use case within your app. Maybe most things use a classical model, but then on certain screens you switch to an event-driven one. Or vice versa. Either way you'll want to read my next post where I will talk about the nuances of implementing an event driven architecture.

Friday, December 02, 2011

The boom in mobile applications has been fueled by excellent application frameworks from Apple and Google. Cocoa Touch and Android take some very different approaches on many things, but both enable developers to create applications that end users enjoy. Of course "excellent" can be a relative term, and in this case the main comparison is web application development. For both experienced and novice developers, it takes less effort to be more productive developing a native mobile application than a web application (mobile or not.) This despite the fact that you really have to deal with a lot more complexity in a mobile app (memory, threads, etc.) than you do for web applications.

Despite having significant advantages over web development, mobile applications often have some similar qualities and this often leads to similar limitations. Most mobile applications are network based. They use the network to get information and allow you to interact with other users. Before mobile applications, this was the realm of web applications. Mobile apps have shown that there is not necessary to use a browser to host an application that is network based. That's good. However the way that mobile apps interact with servers over the network has tended to resemble the way that web applications do this. Here's a picture that shows this.
This diagram shows a traditional mobile application's architecture. In particular it shows an Android app, hence that little red box on the right saying C2DM, which we will talk more about later. Most of this is applicable to iOS as well though. Most apps get data from servers or send data to servers using HTTP, the same protocol used by web browsers. HTTP is wonderfully simple in most ways. Significantly, it is a short-lived, synchronous communication. You make a request and you wait until you get a response. You then use the response to update the state of your application, show things to the user, etc.

Now since HTTP is synchronous and network access is notoriously slow (especially for mobile apps), you must inevitably banish HTTP communication to a different thread than the one where you respond to user interactions. This simple paradigm becomes the basis for how many mobile applications are built. Android provides some nice utilities for handling this scenario like AsyncTask and Loaders. Folks from the Android team have written numerous blogs and presentations on the best way to setup an application that follows this pattern, precisely because this pattern is so prevalent in mobile applications. It is the natural first step from web application to mobile application as you can often re-use much of the backend systems that you used for web applications.

Before we go any further, take another look at the diagram. I promised to talk more about it. That is the cloud-to-device messaging system that is part of Android (or at least Google's version, it's not available on the Kindle Fire for example.) It provides a way for data to get to the application without the usual HTTP. Your server can send a message to C2DM servers, which will then "push" the message to the device and your app. This is done through a persistent TCP socket between the device and the C2DM servers. Now these messages are typically very small, so often it is up to your application to retrieve additional data -- which could very well go back to using HTTP. Background services on Android can makes this very simple to do.

Notice that in the previous paragraph we never once used the word "notification." C2DM was seen by many as Android's equivalent to Apple's Push Notifications. They can definitely fulfill the same use cases. Once your service receives the message it can then choose to raise a notification on the device for the user to respond to. But C2DM is not limited to notifications, bot by a long shot. Publishing a notification is just one of many things that your application can do with the message that it receives from C2DM. What is most interesting about C2DM is that leads us into another type of application architecture not built around HTTP. In part 2 of this post we will take a deeper look at event-driven architectures.